Lower testosterone levels predict incident stroke and transient ischemic attack in older men

Evaluating the impact of testosterone replacement therapy on carotid atherosclerosis: a systematic review and meta-analysis

Aim: This meta-analysis investigates the association between testosterone replacement therapy [TRT] and carotid artery atherosclerosis. Methods: 3 databases were searched for studies up to June 2023 per the PRISMA guidelines. The eligibility criteria comprised RCTs and observational studies involving hypogonadal males receiving exogenous testosterone, in which CIMT was assessed. CAA was the primary outcome, whereas secondary outcomes included HDL, LDL, CRP, total cholesterol and total testosterone. The statistical analysis was performed using Review Manager. Results: Statistical analysis revealed no association between TRT and assessed outcomes. There was a significant increase in total testosterone levels, depicting indirect anti-atherosclerotic effects of TRT. Conclusion: Meta-analysis shows no relation between TRT and CIMT or other markers, allowing its safe usage for hypogonadal males.

Beyond T-Trials, T4DM and TRAVERSE: the next large testosterone randomized controlled trial

PURPOSE OF REVIEW

Lower testosterone concentrations have been associated with poorer health outcomes in ageing men, but proving causality and demonstrating potential for therapeutic benefit requires randomized clinical trials (RCTs). This review discusses recent observational findings and results of major testosterone RCTs, to explore the need for another, larger trial.

RECENT FINDINGS

Evidence of Leydig cell impairment emerges in men above the age of 70 years. Lower testosterone is associated with diabetes risk, and also risk of incident dementia. An individual participant data meta-analysis found that below thresholds of testosterone of 7.4 nmol/L and 5.3 nmol/l respectively, risks of all-cause mortality and cardiovascular deaths in men increased. Testosterone for the Prevention of Type 2 Diabetes Mellitus (T4DM), a multicentre RCT, showed that testosterone treatment prevented or reverted type 2 diabetes in men at high risk. Testosterone Replacement Therapy for Assessment of Long-term Vascular Events and Efficacy Response in Hypogonadal Men (TRAVERSE), a cardiovascular safety trial, demonstrated cardiovascular and prostate safety of testosterone treatment in men with or at risk of cardiovascular disease. T4DM confirmed findings from the Testosterone Trials (T-Trials) that testosterone improved sexual function, and bone microarchitecture and density. However, in TRAVERSE, testosterone-treated men had a higher risk of clinical bone fractures, but not major osteoporotic fractures.

SUMMARY

Men with disorders of the hypothalamic-pituitary-testicular (HPT) axis causing androgen deficiency warrant consideration for testosterone therapy. In men with an intact HPT axis, testosterone treatment is a pharmacological intervention which requires justification from high quality RCT data. Currently, there is insufficient evidence to justify wider use of testosterone for prevention of cardiometabolic disease. However, there is scope for another large testosterone RCT to investigate whether testosterone treatment might, in older men, extend disability-free survival.

Metabolic benefits afforded by estradiol and testosterone in both sexes: clinical considerations

Testosterone (T) and 17β-estradiol (E2) are produced in male and female humans and are potent metabolic regulators in both sexes. When E2 and T production stops or decreases during aging, metabolic dysfunction develops and promotes degenerative metabolic and vascular disease. Here, we discuss the shared benefits afforded by E2 and T for metabolic function human females and males. In females, E2 is central to bone and vascular health, subcutaneous adipose tissue distribution, skeletal muscle insulin sensitivity, antiinflammatory immune function, and mitochondrial health. However, T also plays a role in female skeletal, vascular, and metabolic health. In males, T's conversion to E2 is fundamental to bone and vascular health, as well as prevention of excess visceral adiposity and the promotion of insulin sensitivity via activation of the estrogen receptors. However, T and its metabolite dihydrotestosterone also prevent excess visceral adiposity and promote skeletal muscle growth and insulin sensitivity via activation of the androgen receptor. In conclusion, T and E2 are produced in both sexes at sex-specific concentrations and provide similar and potent metabolic benefits. Optimizing levels of both hormones may be beneficial to protect patients from cardiometabolic disease and frailty during aging, which requires further study.

The association of cortisol, testosterone, and cortisol/testosterone ratio with stroke: A cross-sectional study

AIMS

We aimed to investigate the association between serum cortisol, testosterone, and cortisol/testosterone (C/T) ratio and stroke.

MATERIALS AND METHODS

A total of 6157 subjects were included in this study. The serum levels of cortisol and testosterone were determined by liquid chromatography-tandem mass spectrometry method. The relationships of serum cortisol, testosterone, and C/T ratio levels with the odds ratios (ORs) of stroke were calculated using logistic regression analysis. The dose-response associations between serum cortisol, testosterone, and C/T ratio levels with stroke estimated by restricted cubic splines.

RESULTS

After adjusting for multiple variables, serum testosterone levels were negactively associated with stroke in males (per 1 unit, odds ratio (OR) = 0.83, 95 % confidence interval (CI): 0.70, 0.97). The serum C/T ratio is positively associated with stroke in both males and females (OR = 1.16, 95 % CI:1.04,1.34 in males and OR = 1.15, 95 % CI:1.02,1.31 in females). Restricted cubic splines showed a significant linear dose-response relationship between testosterone and C/T ratio and stroke in males (P for overall association <0.05, P for nonlinearity >0.05).

CONCLUSION

Our study findings show that serum testosterone levels are negatively correlated with stroke in males; meanwhile, serum C/T ratio is positively correlated with stroke in both males and females.

Current View on PPAR-α and Its Relation to Neurosteroids in Alzheimer's Disease and Other Neuropsychiatric Disorders: Promising Targets in a Therapeutic Strategy

Peroxisome proliferator-activated receptors (PPARs) may play an important role in the pathomechanism/pathogenesis of Alzheimer's disease (AD) and several other neurological/neuropsychiatric disorders. AD leads to progressive alterations in the redox state, ion homeostasis, lipids, and protein metabolism. Significant alterations in molecular processes and the functioning of several signaling pathways result in the degeneration and death of synapses and neuronal cells, leading to the most severe dementia. Peroxisome proliferator-activated receptor alpha (PPAR-α) is among the processes affected by AD; it regulates the transcription of genes related to the metabolism of cholesterol, fatty acids, other lipids and neurotransmission, mitochondria biogenesis, and function. PPAR-α is involved in the cholesterol transport to mitochondria, the substrate for neurosteroid biosynthesis. PPAR-α-coding enzymes, such as sulfotransferases, which are responsible for neurosteroid sulfation. The relation between PPAR-α and cholesterol/neurosteroids may have a significant impact on the course and progression of neurodegeneration/neuroprotection processes. Unfortunately, despite many years of intensive studies, the pathogenesis of AD is unknown and therapy for AD and other neurodegenerative diseases is symptomatic, presenting a significant goal and challenge today. This review presents recent achievements in therapeutic approaches for AD, which are targeting PPAR-α and its relation to cholesterol and neurosteroids in AD and neuropsychiatric disorders.

A protective role of genetically predicted sex hormone-binding globulin on stroke

Introduction

The role of sex hormone-binding globulin (SHBG) on stroke has been investigated in several observational studies. To provide the causal estimates of SHBG on stroke and its subtypes, bi-directional and multivariable Mendelian randomization (MR) analyses are performed.

Methods

The genetic instruments of SHBG were obtained from the UK Biobank. Outcome datasets for stroke and its subtypes were taken from the MEGASTROKE Consortium. The main analysis used in this study is the inverse variance weighting, complemented by other sensitivity approaches to verify the conformity of findings.

Results

We found that the risk of stroke grew by 13% (odd ratio [OR] = 0.87, 95% confidence interval [CI] = 0.79-0.95, P = 0.0041) and the risk of ischemic stroke grew by 15% (OR = 0.85, 95%CI = 0.77-0.95, P = 0.0038) caused by genetically predicted SHBG. The causal association remains robust in the reverse MR and multivariable MR analyses for stroke (reverse MR: all P > 0.01 for the IVW method; MVMR: OR = 0.72, 95%CI = 0.59-0.87, P = 0.0011) and ischemic stroke (reverse MR: all P > 0.01 for IVW; MVMR: OR = 0.70, 95%CI = 0.56-0.86, P = 0.0007).

Conclusion

Our MR study provides novel evidence that SHBG has an inverse association with stroke and ischemic stroke, exerting protective effects on stroke.

Testosterone replacement therapy and vascular thromboembolic events: a systematic review and meta-analysis

To evaluate the relationship between testosterone replacement therapy (TRT) and arterial and/or venous thrombosis in patients with pre-treatment total testosterone (TT) <12 nmol l -1 , we performed a meta-analysis following the Population Intervention Comparison Outcome model. Population: men with TT <12 nmol l -1 or clear mention of hypogonadism in the inclusion criteria of patients; intervention: TRT; comparison: placebo or no therapy; outcomes: arterial thrombotic events (stroke, myocardial infarction [MI], upper limbs, and lower limbs), VTE (deep vein thrombosis [DVT], portal vein thrombosis, splenic thrombosis, and pulmonary embolism), and mortality. A total of 2423 abstracts were assessed for eligibility. Twenty-four studies, including 14 randomized controlled trials (RCTs), were finally included, with a total of 4027 and 310 288 hypotestosteronemic male patients, from RCTs and from observational studies, respectively. Based on RCT-derived data, TRT did not influence the risk of arterial thrombosis (odds ratio [OR] = 1.27, 95% confidence interval [CI]: 0.47-3.43, P = 0.64), stroke (OR = 1.34, 95% CI: 0.09-18.97, P = 0.83), MI (OR = 0.51, 95% CI: 0.11-2.31, P = 0.39), VTE (OR = 1.42, 95% CI: 0.22-9.03, P = 0.71), pulmonary embolism (OR = 1.38, 95% CI: 0.27-7.04, P = 0.70), and mortality (OR = 0.70, 95% CI: 0.20-2.38, P = 0.56). Meanwhile, when only observational studies are considered, a significant reduction in the risk of developing arterial thrombotic events, MI, venous thromboembolism, and mortality was observed. The risk for DVT remains uncertain, due to the paucity of RCT-based data. TRT in men with TT <12 nmol l -1 is safe from the risk of adverse cardiovascular events. Further studies specifically assessing the risk of DVT in men on TRT are needed.

Associations of Serum Testosterone and Sex Hormone-binding Globulin With Incident Arrhythmias in Men From UK Biobank

CONTEXT

Sex hormones have been identified as cardiovascular risk factors, whereas the relationship between sex hormones and the risk of arrhythmias in men has not yet been well studied in the prospective cohort study.

OBJECTIVE

To analyze associations of serum testosterone and SHBG concentrations and calculate free testosterone (cFT) with arrhythmias in men.

METHODS

Sex hormones were measured at baseline from UK Biobank. Main outcomes were incidence of atrial fibrillation/flutter (AF), ventricular arrhythmia (VA), and bradyarrhythmia (BA).

RESULTS

Of 173 498 men (aged 37-73 years, followed for 11 years), 11 368 had incident AF, 1646 had incident VA, and 4788 had incident BA. Compared with the third quartiles, the lowest category of serum testosterone was associated with increased risks of AF (hazard ratio [HR], 1.06; 95% CI, 1.00-1.12) and BA (HR, 1.11; 95% CI, 1.02-1.20) after multivariable adjustment, but no VA. Likewise, similar associations were found between cFT values and AF and BA events. Furthermore, higher levels of cFT were associated with increased risks of AF (HR, 1.07; 95% CI, 1.02-1.13) and VA (HR, 1.18; 95% CI, 1.01-1.37). Higher SHBG concentrations were associated with increased risks of AF (HR, 1.44; 95% CI, 1.34-1.54), VA (HR, 1.27; 95% CI, 1.07-1.52), and BA (HR, 1.17; 95% CI ,1.05-1.29).

CONCLUSIONS

Lower levels of testosterone and cFT were associated with increased risk of AF and BA. Higher cFT levels were associated with increased risk of AF and VA. Higher SHBG levels were associated with increased risk of AF, VA, and BA.

Testosterone and aging male, a perspective from a developing country

PURPOSE

Hypogonadism is associated with a wide range of physical and psychological symptoms that can affect the overall health of men. However, in a developing country, there are several imposing challenges in the diagnosis and treatment of hypogonadism, including a lack of awareness and understanding of the condition among healthcare providers and patients, limited resources and the high cost of treatment. This review aimed to examine the potential benefits and risks of testosterone replacement therapy (TRT) and provides a perspective of a developing country on the topic.

MATERIALS AND METHODS

A comprehensive literature review was conducted to gather relevant information on the impact of testosterone deficiency on ageing males and the effectiveness of TRT for treating hypogonadism. Published peer-reviewed articles were analyzed to evaluate the benefits and risks of TRT. Additionally, the unique challenges faced in the diagnosis and treatment of hypogonadism in a developing country were considered.

RESULTS

Testosterone replacement therapy has been shown to be an effective treatment for hypogonadism, particularly in symptomatic men with low testosterone levels. It offers potential benefits such as improvements in symptoms and overall quality of life. However, there are associated risks and side effects that need to be considered. In a developing country, challenges such as limited awareness and understanding of hypogonadism, resource constraints, and high treatment costs pose additional barriers to accessing TRT and comprehensive care.

CONCLUSION

In conclusion, TRT holds promise as a treatment for hypogonadism, but its implementation and accessibility face significant challenges in a developing country. Addressing these challenges, including raising awareness, allocating resources, and finding cost-effective solutions, is crucial for ensuring that men with hypogonadism in such settings receive appropriate diagnosis and treatment. Further research and efforts are needed to improve the management of hypogonadism in developing countries and optimize the potential benefits of TRT for affected individuals.

New Horizons: Testosterone or Exercise for Cardiometabolic Health in Older Men

Middle-aged and older men have typically accumulated comorbidities, are increasingly sedentary, and have lower testosterone concentrations (T) compared to younger men. Reduced physical activity (PA) and lower T both are associated with, and may predispose to, metabolically adverse changes in body composition, which contribute to higher risks of cardiometabolic disease. Exercise improves cardiometabolic health, but sustained participation is problematic. By contrast, rates of T prescription have increased, particularly in middle-aged and older men without organic diseases of the hypothalamus, pituitary, or testes, reflecting the unproven concept of a restorative hormone that preserves health. Two recent large randomized trials of T, and meta-analyses of randomized trials, did not show a signal for adverse cardiovascular (CV) events, and T treatment on a background of lifestyle intervention reduced type 2 diabetes by 40% in men at high risk. Men with both higher endogenous T and higher PA levels have lower CV risk, but causality remains unproven. Exercise training interventions improve blood pressure and endothelial function in middle-aged and older men, without comparable benefits or additive effects of T treatment. Therefore, exercise training improves cardiometabolic health in middle-aged and older men when effectively applied as a supervised regimen incorporating aerobic and resistance modalities. Treatment with T may have indirect cardiometabolic benefits, mediated via favorable changes in body composition. Further evaluation of T as a pharmacological intervention to improve cardiometabolic health in aging men could consider longer treatment durations and combination with targeted exercise programs.

Estrogen-mediated mechanisms in hypertension and other cardiovascular diseases

Cardiovascular disease (CVD) is the leading cause of death globally for men and women. Premenopausal women have a lower incidence of hypertension and other cardiovascular events than men of the same age, but diminished sex differences after menopause implicates 17-beta-estradiol (E2) as a protective agent. The cardioprotective effects of E2 are mediated by nuclear estrogen receptors (ERα and ERβ) and a G protein-coupled estrogen receptor (GPER). This review summarizes both established as well as emerging estrogen-mediated mechanisms that underlie sex differences in the vasculature during hypertension and CVD. In addition, remaining knowledge gaps inherent in the association of sex differences and E2 are identified, which may guide future clinical trials and experimental studies in this field.

Sex Difference in Capillary Reperfusion After Transient Middle Cerebral Artery Occlusion in Diabetic Mice

BACKGROUND

Type 2 diabetes (DM2) exacerbates stroke injury, reduces efficacy of endovascular therapy, and worsens long-term functional outcome. Sex differences exist in stroke incidence, response to therapy, poststroke microvascular dysfunction, and functional recovery. In this study, we tested the hypotheses that poor outcome after stroke in the setting of DM2 is linked to impaired microvascular tissue reperfusion and that male and female DM2 mice exhibit different microvascular reperfusion response after transient middle cerebral artery occlusion (MCAO).

METHODS

Transient MCAO was induced for 60 minutes using an intraluminal filament in young adult DM2 and nondiabetic control male and female mice. Capillary flux in deep cortical layers was assessed using optical coherence tomography-based optical microangiography (OMAG), and associated regional brain infarct size was evaluated by hematoxylin and eosin staining.

RESULTS

Compared to baseline, MCAO reduced absolute capillary red blood cell flux by 84% at 24 hours post-MCAO in male DM2 (P<0.001) but not male control mice. When normalized to pre-MCAO baseline, red blood cell flux 24 hours after stroke was 64% lower in male DM2 mice than male nondiabetic controls (P<0.01). In females, MCAO decreased capillary flux by 48% at 24 hours post-MCAO compared with baseline in DM2 (P<0.05) but not in control mice. Red blood cell flux of female DM2 mice did not differ from that of nondiabetic controls either before or 24 hours after MCAO. Furthermore, normalized capillary flux 24 hours after MCAO failed to differ between female DM2 mice and nondiabetic controls. Concomitantly, male but not female DM2 mice experienced 25% larger infarct in caudate-putamen versus respective nondiabetic controls (P<0.05).

CONCLUSIONS

DM2 impairs capillary perfusion and exacerbates ischemic deep brain injury in male but not female young adult mice. Premenopausal females appear to be protected against DM2-related capillary dysfunction and brain injury.

Research progress on the role of hormones in ischemic stroke

Ischemic stroke is a major cause of death and disability around the world. However, ischemic stroke treatment is currently limited, with a narrow therapeutic window and unsatisfactory post-treatment outcomes. Therefore, it is critical to investigate the pathophysiological mechanisms following ischemic stroke brain injury. Changes in the immunometabolism and endocrine system after ischemic stroke are important in understanding the pathophysiological mechanisms of cerebral ischemic injury. Hormones are biologically active substances produced by endocrine glands or endocrine cells that play an important role in the organism's growth, development, metabolism, reproduction, and aging. Hormone research in ischemic stroke has made very promising progress. Hormone levels fluctuate during an ischemic stroke. Hormones regulate neuronal plasticity, promote neurotrophic factor formation, reduce cell death, apoptosis, inflammation, excitotoxicity, oxidative and nitrative stress, and brain edema in ischemic stroke. In recent years, many studies have been done on the role of thyroid hormone, growth hormone, testosterone, prolactin, oxytocin, glucocorticoid, parathyroid hormone, and dopamine in ischemic stroke, but comprehensive reviews are scarce. This review focuses on the role of hormones in the pathophysiology of ischemic stroke and discusses the mechanisms involved, intending to provide a reference value for ischemic stroke treatment and prevention.

Androgens and Androgen Receptors as Determinants of Vascular Sex Differences Across the Lifespan

Androgens, including testosterone and its more potent metabolite dihydrotestosterone, exert multiple actions in the body. Physiologically, they play a critical role in male sex development. In addition, they influence vascular function, including arterial vasodilation and mediation of myogenic tone. Androgens are produced from 9 weeks' gestation in the human fetal testis, as well as in small amounts by the adrenal glands. Serum concentrations vary according to age and sex. The vasculature is a target for direct actions of androgens, which bind to various sex hormone receptors expressed in endothelial and vascular smooth muscle cells. Androgens exert both vasoprotective and vasoinjurious effects, depending on multiple factors including sex-specific effects of androgens, heterogeneity of the vascular endothelium, differential expression of androgen and sex hormone receptors in endothelial and vascular smooth muscle cells, and the chronicity of androgen administration. Long-term administration of androgens induces vasoconstriction and influences endothelial permeability, whereas acute administration may have opposite effects. At the cellular level, androgens stimulate endothelial cell production of nitric oxide and inhibit proinflammatory signalling pathways, inducing vasorelaxation and vasoprotection. However, androgens also activate endothelial production of vasoconstrictors and stimulate recruitment of endothelial progenitor cells. In humans, both androgen deficiency and androgen excess are associated with increased cardiovascular morbidity and mortality. This review discusses how androgens modulate vascular sex differences across the lifespan by considering the actions and production of androgens in both sexes and describes how cardiovascular risk is altered as levels of androgens change with aging.

Relationships between endogenous and exogenous testosterone and cardiovascular disease in men

In this narrative review, we discuss the evidence about the controversy about the cardiovascular effects of endogenous and exogenous testosterone in men. Prospective cohort studies with follow-up of ~5-15 years generally indicate no association or a possible inverse relationship between serum endogenous testosterone concentrations and composite major cardiovascular events, cardiovascular deaths and overall mortality. Pharmacoepidemiological studies of large databases generally show no association between testosterone therapy and incident major cardiovascular events, and some pharmacoepidemiological studies demonstrate an association with decreased overall mortality. Randomized, placebo-controlled trials indicate that there is no increased incidence of overall major cardiovascular events with 1-3 years of testosterone therapy. These placebo-controlled trials have major limitations including small numbers of participants, short duration of testosterone therapy and follow-up, and lack of systematic adjudication of cardiovascular events. Overall, the evidence indicates that endogenous testosterone concentrations and testosterone therapy at physiological dosages confer no or minimal effects on the incidence of cardiovascular outcomes. There is insufficient evidence to make conclusions about testosterone therapy for patients at high risk of cardiovascular events (e.g., men with recent myocardial infarctions or stroke and men with recurrent idiopathic deep venous thromboses). In general, clinicians should avoid prescribing supraphysiological testosterone therapy to hypogonadal men or men with slightly low to low-normal serum testosterone concentrations and no identified disorder of the hypothalamus-pituitary-testicular axis because of the uncertain cardiovascular risks and the lack of proven health benefits. For most men with bona fide hypogonadism, benefits of testosterone therapy exceed the potential risk of adverse cardiovascular effects.

The correlation between testosterone and stroke and the mediating role of blood pressure: The Henan rural cohort study

AIMS

We aimed to investigate the association of serum testosterone with stroke and calculate the proportion explained by blood pressure on this association.

MATERIALS AND METHODS

A total of 6175 subjects were included in this study. Serum testosterone was quantified by liquid chromatography-tandem mass spectrometry. The logistic regression model was used to evaluate the association between serum testosterone and stroke. Linear regression analysis was used to assess the associations of serum testosterone with blood pressure. In addition, mediation analysis was performed to identify the mediation effects of blood pressure on the association of serum testosterone with stroke. Sex-stratified analysis was employed throughout the research.

RESULTS

After adjusting for multiple variables, serum testosterone levels were negatively associated with stroke in males (per 1 unit natural log-transformed, odds ratio (OR) = 0.81, 95% confidence interval (CI): 0.69-0.94; Tertile 3 vs Tertile 1, OR = 0.65, 95% CI:0.44-0.96). Furthermore, blood pressure played a partial mediating role in the relationship between testosterone and stroke in males. The indirect effect/total effect of systolic blood pressure, diastolic blood pressure and mean arterial pressure were 7.37%, 9.54% and 9.22%, respectively. Notably, the relationship between testosterone and stroke and the role of blood pressure in regulating them was not observed in females.

CONCLUSION

This study describes that in rural Chinese males, testosterone can reduce the risk of stroke by affecting blood pressure. To some extent, we provide a new epidemiological evidence for the relationship between testosterone and stroke.

The role of serum testosterone and dehydroepiandrosterone sulfate in kidney function and clinical outcomes in chronic kidney disease: a systematic review and meta-analysis

OBJECTIVE/DESIGN

Testosterone might mediate sex differences in kidney function and chronic kidney disease (CKD). However, few studies analyzing the association between testosterone and kidney function showed conflicting results. Therefore, we performed a systematic review and meta-analysis.

METHODS

Six electronic databases were searched from inception to March 4, 2020, for studies that investigated the association of (i) testosterone status with kidney function in the general population or (ii) testosterone status with clinical outcomes (kidney function decline, kidney failure, cardiovascular (CV) events, and cardiovascular and all-cause mortality) in CKD patients. We used random and fixed-effect models to obtain pooled effect estimates with 95% confidence intervals (CIs).

RESULTS

No randomized-controlled trials that met the inclusion criteria were identified. One study was conducted in the general population and reported an increased risk of incident CKD with low vs normal testosterone (hazard ratio (HR): 1.38, 95% CI: 1.05;1.80). Seven studies were conducted in men with CKD and included testosterone as determinant, of which six could be meta-analyzed. Low testosterone was associated with an increased risk of all-cause mortality and CV events (pooled HR: 1.98, 95% CI: 1.36;2.89; pooled HR of 2.40, 95% CI: 1.22;4.71, respectively). Two studies showed an increased risk of all-cause mortality with decreased dehydroepiandrosterone sulfate (DHEAS) in men with CKD; results regarding CV events were conflicting.

CONCLUSIONS

Although literature is scarce, evidence suggests that lower testosterone may increase CKD risk in the general population and risk of all-cause mortality and CV events in men with CKD. Whether testosterone supplementation could prevent these potential detrimental outcomes should be determined in future intervention studies.

Evaluation of the Interaction of Sex Hormones and Cardiovascular Function and Health

Purpose of Review

Sex hormones drive development and function of reproductive organs or the development of secondary sex characteristics but their effects on the cardiovascular system are poorly understood. In this review, we identify the gaps in our understanding of the interaction between sex hormones and the cardiovascular system.

Recent Findings

Studies are progressively elucidating molecular functions of sex hormones in specific cell types in parallel with the initiation of crucial large randomized controlled trials aimed at improving therapies for cardiovascular diseases (CVDs) associated with aberrant levels of sex hormones.

Summary

In contrast with historical assumptions, we now understand that men and women show different symptoms and progression of CVDs. Abnormal levels of sex hormones pose an independent risk for CVD, which is apparent in conditions like Klinefelter syndrome, androgen insensitivity syndrome, and menopause. Moreover, sex hormone–based therapies remain understudied and may not be beneficial for cardiovascular health.

Testosterone deficiency and the aging male

Testosterone deficiency (TD), also known as male hypogonadism, is a complex syndrome encompassing physical, biochemical, and social aspects that increasingly affects the aging population. TD has been analyzed over recent decades, with an enhanced focus on etiologies relating to aging males. There is debate whether testosterone decline leading to hypogonadism is directly and primarily related to age-specific processes or if it is the subsequent result of accumulating comorbidities throughout a lifetime. Several studies have been done to further characterize this distinction. Chronic comorbidities that have commonly been associated with TD include hypertension (HTN), cardiovascular disease (CVD), diabetes mellitus (DM), obesity, metabolic syndrome (MetS), chronic kidney disease (CKD), and tobacco use. Although clear associations between hypogonadism and aging have been biochemically demonstrated, many large studies have illustrated the concomitant effects of highly prevalent chronic diseases and social behaviors in aging men. Given the significant impact of hypogonadism on the physical and mental health of men, this paper aims to delve into these studies and further define the complex relationship of testosterone deficiency in the aging male.

Sex differences in the blood-brain barrier: Implications for mental health

Prevalence of mental disorders, including major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SZ) are increasing at alarming rates in our societies. Growing evidence points toward major sex differences in these conditions, and high rates of treatment resistance support the need to consider novel biological mechanisms outside of neuronal function to gain mechanistic insights that could lead to innovative therapies. Blood-brain barrier alterations have been reported in MDD, BD and SZ. Here, we provide an overview of sex-specific immune, endocrine, vascular and transcriptional-mediated changes that could affect neurovascular integrity and possibly contribute to the pathogenesis of mental disorders. We also identify pitfalls in current literature and highlight promising vascular biomarkers. Better understanding of how these adaptations can contribute to mental health status is essential not only in the context of MDD, BD and SZ but also cardiovascular diseases and stroke which are associated with higher prevalence of these conditions.

The Role of Testosterone in the Elderly: What Do We Know?

Testosterone is the most important hormone in male health. Aging is characterized by testosterone deficiency due to decreasing testosterone levels associated with low testicular production, genetic factors, adiposity, and illness. Low testosterone levels in men are associated with sexual dysfunction (low sexual desire, erectile dysfunction), reduced skeletal muscle mass and strength, decreased bone mineral density, increased cardiovascular risk and alterations of the glycometabolic profile. Testosterone replacement therapy (TRT) shows several therapeutic effects while maintaining a good safety profile in hypogonadal men. TRT restores normal levels of serum testosterone in men, increasing libido and energy level and producing beneficial effects on bone density, strength and muscle as well as yielding cardioprotective effects. Nevertheless, TRT could be contraindicated in men with untreated prostate cancer, although poor findings are reported in the literature. In addition, different potential side effects, such as polycythemia, cardiac events and obstructive sleep apnea, should be monitored. The aim of our review is to provide an updated background regarding the pros and cons of TRT, evaluating its role and its clinical applicability in different domains.

The Role of Testosterone in the Elderly: What Do We Know?

Testosterone is the most important hormone in male health. Aging is characterized by testosterone deficiency due to decreasing testosterone levels associated with low testicular production, genetic factors, adiposity, and illness. Low testosterone levels in men are associated with sexual dysfunction (low sexual desire, erectile dysfunction), reduced skeletal muscle mass and strength, decreased bone mineral density, increased cardiovascular risk and alterations of the glycometabolic profile. Testosterone replacement therapy (TRT) shows several therapeutic effects while maintaining a good safety profile in hypogonadal men. TRT restores normal levels of serum testosterone in men, increasing libido and energy level and producing beneficial effects on bone density, strength and muscle as well as yielding cardioprotective effects. Nevertheless, TRT could be contraindicated in men with untreated prostate cancer, although poor findings are reported in the literature. In addition, different potential side effects, such as polycythemia, cardiac events and obstructive sleep apnea, should be monitored. The aim of our review is to provide an updated background regarding the pros and cons of TRT, evaluating its role and its clinical applicability in different domains.

Genetic, Molecular, and Cellular Determinants of Sex-Specific Cardiovascular Traits

Despite the well-known sex dimorphism in cardiovascular disease traits, the exact genetic, molecular, and cellular underpinnings of these differences are not well understood. A growing body of evidence currently points at the links between cardiovascular disease traits and the genome, epigenome, transcriptome, and metabolome. However, the sex-specific differences in these links remain largely unstudied due to challenges in bioinformatic methods, inadequate statistical power, analytic costs, and paucity of valid experimental models. This review article provides an overview of the literature on sex differences in genetic architecture, heritability, epigenetic changes, transcriptomic signatures, and metabolomic profiles in relation to cardiovascular disease traits. We also review the literature on the associations between sex hormones and cardiovascular disease traits and discuss the potential mechanisms underlying these associations, focusing on human studies.

Associations of Serum Testosterone and Sex Hormone-Binding Globulin With Incident Cardiovascular Events in Middle-Aged to Older Men

BACKGROUND

The influence of testosterone on risk for cardiovascular events in men is uncertain. Previous observational studies of sex hormones and incident cardiovascular disease in men have reported inconsistent findings, limited by cohort sizes and different selection criteria.

OBJECTIVE

To analyze associations of serum total testosterone and sex hormone-binding globulin (SHBG) with incident cardiovascular events in men.

DESIGN

Cohort study.

SETTING

UK Biobank prospective cohort.

PARTICIPANTS

Community-dwelling men aged 40 to 69 years.

MEASUREMENTS

Testosterone and SHBG were assayed, and free testosterone was calculated. Cox proportional hazards regression was done, with outcomes of incident myocardial infarction (MI), hemorrhagic stroke (HS), ischemic stroke (IS), heart failure (HF), and major adverse cardiovascular events (MACE), adjusted for sociodemographic, lifestyle, and medical factors.

RESULTS

Of 210 700 men followed for 9 years, 8790 (4.2%) had an incident cardiovascular event. After adjustment for key variables, lower total testosterone concentrations (quintile 1 vs. quintile 5) were not associated with incident MI (fully adjusted hazard ratio [HR], 0.89 [95% CI, 0.80 to 1.00]), HS (HR, 0.94 [CI, 0.70 to 1.26]), IS (HR, 0.95 [CI, 0.82 to 1.10]), HF (HR, 1.15 [CI, 0.91 to 1.45]), or MACE (HR, 0.92 [CI, 0.84 to 1.00]). Men with lower calculated free testosterone values had a lower incidence of MACE (HR, 0.90 [CI, 0.84 to 0.97]). Lower SHBG concentrations were associated with higher incidence of MI (HR, 1.23 [CI, 1.09 to 1.38]) and lower incidence of IS (HR, 0.79 [CI, 0.67 to 0.94]) and HF (HR, 0.69 [CI, 0.54 to 0.89]), but not with HS (HR, 0.81 [CI, 0.57 to 1.14]) or MACE (HR, 1.01 [CI, 0.92 to 1.11]).

LIMITATION

Observational study; single baseline measurement of testosterone and SHBG.

CONCLUSION

Men with lower total testosterone concentrations were not at increased risk for MI, stroke, HF, or MACE. Calculated free testosterone may be associated with risk for MACE. Men with lower SHBG concentrations have higher risk for MI but lower risk for IS and HF, with causality to be determined.

PRIMARY FUNDING SOURCE

Western Australian Health Translation Network, Medical Research Future Fund, and Lawley Pharmaceuticals.

Low free testosterone level as a predictor of cardiovascular events in Japanese men with coronary risk factors

Aim: We investigated whether low plasma free testosterone (FT) levels could predict cardiovascular events (CVE) in Japanese men with coronary risk factors.Methods: Male patients with classical coronary risk factors who had undergone serum FT testing were enrolled. New incidences of CVE were retrospectively investigated among all eligible participants based on their medical records.Results: Overall, 466 male outpatients with coronary risk factors without a previous history of CVE were identified. Throughout the follow-up period (median = 92 months), 126 CVE occurred. The Kaplan-Meier survival analysis according to the tertiles of plasma FT levels revealed that patients with the lowest FT tertile (<6.5 pg/mL) had a higher likelihood of developing CVE than those with the highest tertile (>9.3 pg/mL) (p<.01). Multivariate analysis showed that increased frequency of CVE was observed with lower FT tertiles, independent of other coronary risk factors, with hazard ratios of 0.617 (95% CI, 0.389-0.976; p=.030) and 0.524 (95% CI, 0.309-0.887; p=.016) for the second and highest tertile relative to the lowest FT tertile, respectively.Conclusion: Among Japanese men with coronary risk factors, a lower FT level was a predictor for the development of cardiovascular diseases independent of other coronary risk factors and age.

Systematic review and meta-analyses on associations of endogenous testosterone concentration with health outcomes in community-dwelling men

OBJECTIVES

The overall study aim is to clarify the relation of endogenous sex hormones with major health outcomes in men. This paper reports a systematic review focusing on published estimates for testosterone associations.

SETTING

Community-dwelling men.

PARTICIPANTS

20 180 adult men participated in the final set of studies identified and selected from a systematic review. Eligible studies included prospective cohort studies with plasma or serum testosterone concentrations measured for adult men using mass spectrometry with at least 5 years of follow-up data and one of the specified outcome measures recorded. Only published or grey literature items written in English were considered.

PRIMARY AND SECONDARY OUTCOME MEASURES

Planned prospective outcome measures: cardiovascular disease (CVD) events, CVD deaths, all-cause mortality, cancer deaths, cancer diagnoses, cognitive decline, dementia. Meta-analyses were of the most frequently reported outcomes in selected studies: CVD deaths and all-cause mortality. Succinct characterisations of testosterone associations with other outcomes are also presented.

RESULTS

Screening of 1994 deduplicated items identified 9 suitable studies, with an additional 2 identified by colleagues (11 in total). Summary estimates of mean testosterone concentration and age at recruitment for 20 180 adult men were 15.4±0.7 nmol/L and 64.9±3.3 year. Despite considerable variation in mean testosterone, a metaregression estimated no significant dependence on mean age at recruitment among studies (slope=-0.03, 95% CI -0.11 to 0.06). Meta-analyses demonstrated negligible heterogeneity and no significant effect of a 5 nmol/L increase in testosterone on the risk of all-cause mortality (HR=0.96, 95% CI 0.89 to 1.03) or death from CVD (HR=0.95, 95% CI 0.83 to 1.08).

CONCLUSIONS

Analyses of published estimates did not demonstrate associations of endogenous testosterone with CVD deaths or with all-cause mortality. Suggested further research includes the planned individual participant data meta-analyses for selected studies, enabling the investigation of non-linear summary effects.

PROSPERO REGISTRATION NUMBER

PROSPERO: CRD42019139668.

Approach to Obesity in the Older Population

Until recently, weight loss in older obese people was feared because of ensuing muscle loss and frailty. Facing overall increasing longevity, high rates of obesity in older individuals (age ≥ 65 years) and a growing recognition of the health and functional cost of the number of obesity years, abetted by evidence that intentional weight loss in older obese people is safe, this approach is gradually, but not unanimously, being replaced by more active principles. Lifestyle interventions that include reduced but sufficient energy intake, age-adequate protein and micronutrient intake, coupled with aerobic and resistance exercise tailored to personal limitations, can induce weight loss with improvement in frailty indices. Sustained weight loss at this age can prevent or ameliorate diabetes. More active steps are controversial. The use of weight loss medications, particularly glucagon-like peptide-1 analogs (liraglutide as the first example), provides an additional treatment tier. Its safety and cardiovascular health benefits have been convincingly shown in older obese patients with type 2 diabetes mellitus. In our opinion, this option should not be denied to obese individuals with prediabetes or other obesity-related comorbidities based on age. Finally, many reports now provide evidence that bariatric surgery can be safely performed in older people as the last treatment tier. Risk-benefit issues should be considered with extreme care and disclosed to candidates. The selection process requires good presurgical functional status, individualized consideration of the sequels of obesity, and reliance on centers that are highly experienced in the surgical procedure as well as short-term and long-term subsequent comprehensive care and support.

Revealing the Influences of Sex Hormones and Sex Differences in Atrial Fibrillation and Vascular Cognitive Impairment

The impacts of sex differences on the biology of various organ systems and the influences of sex hormones on modulating health and disease have become increasingly relevant in clinical and biomedical research. A growing body of evidence has recently suggested fundamental sex differences in cardiovascular and cognitive function, including anatomy, pathophysiology, incidence and age of disease onset, symptoms affecting disease diagnosis, disease severity, progression, and treatment responses and outcomes. Atrial fibrillation (AF) is currently recognized as the most prevalent sustained arrhythmia and might contribute to the pathogenesis and progression of vascular cognitive impairment (VCI), including a range of cognitive deficits, from mild cognitive impairment to dementia. In this review, we describe sex-based differences and sex hormone functions in the physiology of the brain and vasculature and the pathophysiology of disorders therein, with special emphasis on AF and VCI. Deciphering how sex hormones and their receptor signaling (estrogen and androgen receptors) potentially impact on sex differences could help to reveal disease links between AF and VCI and identify therapeutic targets that may lead to potentially novel therapeutic interventions early in the disease course of AF and VCI.

Testosterone therapy and cardiovascular diseases

Since it was first synthesised in 1935, testosterone (T) has been viewed as the mythical Fountain of Youth, promising rejuvenation, restoring sexual appetites, growing stronger muscles, and quicker thinking. T is endowed with direct effects on myocardial and vascular structure and function, as well as on risk factors for cardiovascular (CV) disease. Indeed, low serum T levels are a risk factor for diabetes, metabolic syndrome, inflammation, and dyslipidaemia. Moreover, many studies have shown that T deficiency per se is an independent risk factor of CV and all-cause mortality. On this background and due to direct-to-patient marketing by drug companies, we have witnessed to the widespread use of T replacement therapy (TT) without clear indications particularly in late-life onset hypogonadism. The current review will dwell upon current evidence and controversies surrounding the role of T in the pathophysiology of CV diseases, the link between circulating T levels and CV risk, and the use of replacing T as a possible adjuvant treatment in specific CV disorders. Specifically, recent findings suggest that heart failure and type 2 diabetes mellitus represent two potential targets of T therapy once that a state of hypogonadism is diagnosed. However, only if ongoing studies solve the CV safety issue the T orchid may eventually 'bloom'.

Association of Genetically Predicted Serum Estradiol With Risk of Thromboembolism in Men: A Mendelian Randomization Study

CONTEXT

An association was recently reported between genetic markers related to high testosterone and increased risk of thromboembolism in men, but a possible causal role of estradiol for risk of thromboembolism in men remains unknown.

OBJECTIVE

This work aimed to determine whether endogenous estradiol has a causal role in thromboembolism in men.

METHODS

A 2-sample mendelian randomization study using gene-based genetic instruments assessed the association between endogenous estradiol genetically predicted by 22 variants in the aromatase CYP19A1 gene region and the risk of thromboembolism (5815 cases) in 170 593 unrelated men of White ancestry in the UK Biobank. The main outcome measure included thromboembolism based on self-reports, hospital episodes, and death.

RESULTS

Endogenous estradiol genetically predicted by variants in the CYP19A1 gene region was inversely associated with the risk of thromboembolism (odds ratio per SD increase in estradiol 0.74; 95% CI, 0.62-0.90). In contrast, genetic variants in the JMJD1C gene, used as a predictor of high endogenous testosterone, were associated with an increased risk of thromboembolism (odds ratio per SD increase in testosterone 1.39; 95% CI, 1.12-1.72). Subsequent explorative analyses evaluating potential repercussions of thromboembolism revealed that endogenous estradiol genetically predicted by variants in the CYP19A1 gene region was inversely associated with the risk of ischemic stroke (0.68; 95% CI, 0.49-0.95) but not myocardial infarction (0.97; 95% CI, 0.84-1.13).

CONCLUSION

Genetically predicted estradiol was inversely associated with the risk of thromboembolism and ischemic stroke in men. The ratio between testosterone and estradiol, determined by CYP19A1 activity, may contribute to the overall impact of sex steroids on thromboembolism in men.

Relationship between serum total testosterone and prostate volume in aging men

Total testosterone levels decline with age, while prostate volume and the prevalence of benign prostatic hyperplasia increase with age. We sought to investigate the correlation of serum testosterone levels with prostate volume in aging men. We analyzed clinical data obtained from 416 ostensibly healthy men who underwent routine health check-ups and recruited and collected data from these subjects 4 years later. We analyzed the correlation between prostate volume and relevant factors, as well as the correlation between changes in prostate volume and low testosterone over a 4-year period. Men with low testosterone had significantly larger prostate volume than those in the normal testosterone group (26.86 ± 8.75 vs. 24.06 ± 6.77 P = 0.02), and subjects with low testosterone had significantly higher levels of obesity-related factors, including waist circumference, body mass index, and insulin (all P < 0.001). After adjustment for age, testosterone level was negatively correlated with prostate volume (P = 0.004), and prostate volume and 4-year changes in prostate volume were associated with low testosterone. With increased testosterone level, prostate volume showed a significant linear decreasing trend. These findings provide evidence of the relationship between testosterone and prostate volume. Additional large studies are needed to confirm these preliminary results.

Association of night-time sleep and day napping with the prevalence of MOSH in young obese men

BACKGROUND

Obesity in men is also shown to be associated with reduced reproductive potential, and this particular subtype was described as male obesity-associated secondary hypogonadism (MOSH). Recent studies showing the influence of sleep disorders on testosterone levels suggested a potential role of sleep disorders in determining the development of MOSH.

OBJECTIVES

To assess the association between night-time sleep duration and day napping and the prevalence of MOSH.

MATERIALS AND METHODS

In this cross-sectional study, 226 obese male participants aged 18-30 years were enrolled. Daytime napping and night-time sleep duration data were collected using a standardized self-reported Chinese-language questionnaire. MOSH was defined as obese men (BMI ≥ 30 kg/m² ) with hypogonadal symptoms and decreased total testosterone level and/or free testosterone level, excluding other causes of hypogonadism.

RESULTS

The overall prevalence of MOSH was 48.2% in this study. An inverse association was observed between night sleep duration and the risk of prevalent MOSH. Men who reported fewer than 6 h of night-time sleep had reduced total testosterone and free testosterone levels and an increased risk of MOSH. Further regression analysis revealed that after adjustment for potential confounders, the odds ratio of MOSH for the short night-time sleep group (<6 h vs. 6-8 h) was 6.17 (p = 0.040). No significant association was observed between day napping status and prevalence of MOSH.

DISCUSSION AND CONCLUSION

Short night sleep duration was associated with an increased risk of MOSH in the young obese Chinese population. Chronic sleep curtailment has a negative effect on obese men's health in terms of hypogonadism.

Late-onset hypogonadism: Clinical evidence, biological aspects and evolutionary considerations

The growing life expectancy in modern societies has raised scientific interest in identifying medical interventions to alleviate age-associated pathologies such as vascular calcification, cognitive decline, sarcopenia, osteoporosis and sexual dysfunction. Although no such single treatment has thus far been established in humans, some clinicians and patients have set their hopes on testosterone replacement therapy (TRT) as a potential "fountain of youth" for aging men. While TRT has proven effective in ameliorating distinct symptoms of late-onset hypogonadism (LOH), its safety remains to be demonstrated. Besides humans, multiple other species exhibit age-related reductions in circulating testosterone levels, raising the question whether such changes are an inherent, pathological feature of growing organismal age or rather reflect an adaptive response. In this manuscript, we apply key principles of evolutionary medicine to testosterone biology and LOH to provide a novel perspective on these two fields. Additionally, we discuss insightful data derived from the animal kingdom to illustrate the plasticity of individual testosterone trajectories across the lifespan, outline cost-benefit-considerations of TRT in LOH and highlight potential caveats of such therapies.

Association of Serum Testosterone and Luteinizing Hormone With Blood Pressure and Risk of Cardiovascular Disease in Middle-Aged and Elderly Men

Background

The age‐related decline in testosterone levels is thought to be of great importance for male aging and cardiovascular diseases. However, data are controversial on whether abnormal sex hormones are linked to the presence of cardiovascular diseases and it is also uncertain how blood pressure modifies the association between testosterone levels and major cardiovascular diseases.

Methods and Results

This is a multicenter, population‐based, cross‐sectional study of 6296 men conducted between 2013 and 2016. Basic information and clinical symptoms were obtained by questionnaires. Blood pressure and plasma levels of total testosterone, sex hormone–binding globulin, luteinizing hormone, and free testosterone were determined in men in a multistage random, cluster sampling in 6 provinces of China. There were 5786 Chinese men (mean [SD] age 55.0 [10.1] years) included after exclusion criteria were applied; 37.2% (2150) of them were diagnosed with hypertension. Total testosterone, free testosterone, and sex hormone–binding globulin were inversely associated with the prevalence of hypertension. Age >65 years or body mass index ≥24 negatively impacted the inverse correlation between testosterone levels and hypertension, whereas smoking and family history of hypertension strengthened the correlation. In participants with grade 2 hypertension, total testosterone was positively associated with the presence of stroke, and luteinizing hormone was also positively correlated with cardiovascular and cerebrovascular diseases.

Conclusions

Lower total testosterone could be a promising risk marker for prevalent hypertension. Both low and high levels of testosterone are associated with greater cardiovascular risk. Primary hypogonadism may be a risk marker for major cardiovascular diseases in men with severe hypertension.

Risk of major adverse cardiovascular events among second-line hormonal therapy for metastatic castration-resistant prostate cancer: A real-world evidence study

BACKGROUND

To evaluate the possible major adverse cardiovascular events (MACE) associated with second-line hormonal therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).

METHODS

We performed a population-based real-world cohort study of 4962 prostate cancer patients between 2014 and 2017 utilizing the Chang Gung Research Database of Taiwan. The second-line hormonal therapies included enzalutamide and abiraterone acetate. The outcomes of interest were MACE, including acute coronary syndrome (ACS), ischemic stroke (IS), and heart failure (HF) events that resulted in hospitalization. Cox proportional-hazards models with inverse probability of treatment weighting (IPTW) with propensity scores were used.

RESULTS

After IPTW, 288 patients were prescribed second-line hormonal therapy and 1575 received first-line androgen-deprivation therapy (ADT). Of all patients diagnosed with MACE, the event rates were 2.92% in the second-line hormonal group and 2.22% in the first-line ADT group. The mean follow-up period was 9.52 months for the second-line hormonal group. Patients who received second-line hormonal therapy exhibited a significantly increased risk for MACE (hazard ratio [HR]: 3.15; 95% confidence interval [CI]: 2.03-4.89), ACS (HR: 4.94; 95% CI: 2.36-10.33), and HF (HR: 2.83; 95% CI: 1.53-5.25), compared with the first-line ADT group, but a similar risk for IS was observed in both groups (HR: 1.70; 95% CI: 0.95-3.04).

CONCLUSIONS

The real-world evidence study revealed increased risks for MACE in mCRPC patients receiving second-line hormonal therapy.

Testosterone Therapy and Cardiovascular Risk: A Critical Analysis of Studies Reporting Increased Risk

BACKGROUND

Treatment of "adult-onset hypogonadism" (AOH) with exogenous testosterone therapy (TTh) to raise serum testosterone (T) levels may influence cardiovascular (CV) risk factors in patients with AOH, whereas low endogenous T levels are associated with an increased CV risk and mortality.

AIM

To critically evaluate studies reporting increased CV risk associated with TTh and to provide an overview of the risks and benefits of restoring T levels through exogenous TTh.

METHODS

A review of publications focusing on the association between TTh and increased CV risk was conducted, and the study methodologies and conclusions of each were critically evaluated. Further, recent clinical and epidemiological studies associating AOH or TTh with a change in CV risk, and pertinent hematologic and vascular effects noted in animal studies and in vitro, as well as in clinical practice were also reviewed.

OUTCOMES

A review of the literature shows that untreated testosterone deficiency and/or low T is associated with an increase in CV risk and adverse outcomes, with numerous studies and meta-analyses to support a positive association between exogenous TTh and an improvement in CV risk factors in men with AOH.

RESULTS

Numerous studies in the literature demonstrate the positive benefits of using TTh; however, since 2013, some publications have suggested a link to increased CV risk associated with TTh. A number of these studies retrospectively analyzed insurance claims databases using diagnosis codes, procedures codes, and prescription information. Many reviews published since have pointed out the methodological flaws and debatable conclusions of these studies.

CLINICAL IMPLICATIONS

A careful assessment of the patient's current health status and CV risk factors should be weighed against the benefits and possible risks resulting from TTh, and consideration should be given to deferring treatment pending resolution or stabilization of CV disease or risk factors.

STRENGTHS & LIMITATIONS

In this review, we provide an in-depth analysis of studies reporting increased CV risk with TTh. Many of the studies were not well-designed, randomized, double-blind, prospective clinical trials but rather post hoc analyses of cohort data. These studies may reflect bias in how treatment and nontreatment decisions are made or reflect conclusions based on widely cited methodological flaws.

CONCLUSION

Appropriate patient selection supported by low pre-treatment T levels and monitoring T levels during treatment with the goal of achieving and maintaining physiologic levels all contribute to the safe and effective use of TTh in men with AOH. Khera M, Miner M, Jaffe J, et al. Testosterone Therapy and Cardiovascular Risk: A Critical Analysis of Studies Reporting Increased Risk. J Sex med 2021;18:83-98.

The predictive value of serum testosterone level on the functional outcomes after acute ischemic stroke in males

INTRODUCTION

We aimed to evaluate the predictive value of sex hormone levels on 3-month functional outcomes after acute ischemic stroke (AIS) in males.

MATERIALS AND METHODS

A total of 110 male AIS patients were included in this prospective study. Serum levels of testosterone and estradiol were measured at admission. The National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin Scale (mRS) were measured at admission and after 3 months. A mRS score ≥3 was considered as a poor functional outcome.

RESULTS

The median age of the 110 subjects was 62.0 [23.3] years (range 35-93 years). Univariate logistic regression revealed that bioavailable testosterone, free testosterone, age, NIHSS at admission, mRS at admission, and prior ischemic stroke were associated with a poor functional outcome (mRS score ≥3) at 3 months. In multivariate analysis, only age, NIHSS at admission, and mRS at admission were independent predictors.

CONCLUSIONS

After controlling the covariates, bioavailable and free testosterone levels are not associated with the 3-month mRS in male patients with AIS. Age, NIHSS at admission, and mRS at admission are robust predictors for the functional outcomes.

Recent testosterone drop-off and risk of cardiovascular events

Low baseline testosterone level has been associated with the development of risk factors for cardiovascular disease such as insulin resistance and obesity. In addition to the absolute testosterone level, remarkable changes in testosterone level may have an acute effect on cardiovascular disease development and progression, which has been rarely investigated. In this study, we used a clinical dataset of 376 hypogonadal men whose testosterone levels were measured every six months for up to 11 years from a registry study in Germany, and conducted survival analyses to investigate the effect of testosterone changes since the last visit (time-varying) on the risk of cardiovascular events. Given the potential discrepancies in comorbidity conditions among patients with prior cardiovascular events and those without, all the analyses were stratified by patients' prior cardiovascular event status. We found the effects were not different among patients with prior cardiovascular events and those without. Regardless of patients' prior cardiovascular event status, patients with larger testosterone declines (≥3.12 nmol/L, 90^th percentile) since the last visit were more likely to experience myocardial infarction. In conclusion, recent pronounced testosterone drop-offs may affect the risk of cardiovascular events among hypogonadal men. Future longitudinal studies are needed to confirm our exploratory study findings.

Effect of Testosterone Treatment on Cardiovascular Events in Men: Protocol for a Systematic Literature Review and Meta-Analysis

Background

Testosterone prescriptions have increased dramatically in recent decades, with increasing usage in men. Despite epidemiological associations reported high circulating concentrations of endogenous androgens and low risk of cardiovascular events and mortality, the effects of exogenous androgens in the form of testosterone therapy for maintaining physiological circulating androgen concentrations on the cardiovascular system remain uncertain with no published meta-analysis on this topic.

Objective

The aim of this study was to investigate the effects of prescribed testosterone treatment, in all forms and durations, from well-developed randomized controlled trials, on cardiovascular events in men aged 18 years or older.

Methods

Peer-reviewed journal articles published from 1980 to 2019 will be searched from databases (ie CINAHL [Cumulated Index to Nursing and Allied Health Literature], Embase, Medline, Scopus, Cochrane Controlled Register of Trials as well as the Clinical Trial Registry). Randomized controlled trials or cluster randomized controlled trials with at least one intervention arm of testosterone and a control group of usual care or no testosterone treatment will be included in this review and meta-analysis. Studies on men with previous cardiovascular events or cardiac vascularization (coronary bypass surgery or percutaneous coronary intervention) will be excluded. Data related to primary outcomes such as clinical events of any type of stroke or transient ischemic attack, nonfatal myocardial infarction or acute coronary syndrome, emergency coronary artery revascularization, carotid surgery, cardiac mortality, and all-cause mortality will be extracted for analysis. The criteria for PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) will be followed in the evaluation of evidence.

Results

Search terms have been piloted and finalized. This study will be completed by the end of 2020.

Conclusions

This protocol will guide a systematic literature review of the evidence around prescribed testosterone and its effect on cardiovascular events in men aged 18 years or older. The findings will inform clinical management of hypogonadal men.

Trial Registration

PROSPERO International Prospective Register of Systematic Reviews CRD42019134278; https://tinyurl.com/y6t7ggge

International Registered Report Identifier (IRRID)

PRR1-10.2196/15163

Risk Factors for Incident Stroke and Its Subtypes in China: A Prospective Study

Background

Managing risk factors is crucial to prevent stroke. However, few cohort studies have evaluated socioeconomic factors together with conventional factors affecting incident stroke and its subtypes in China.

Methods and Results

A 2014 to 2016 prospective study from the China National Stroke Screening and Intervention Program comprised 437 318 adults aged ≥40 years without stroke at baseline. There were 2429 cases of first‐ever stroke during a median follow‐up period of 2.1 years, including 2206 ischemic strokes and 237 hemorrhagic strokes. The multivariable Cox regression analysis indicated that age 50 to 59 years (versus 40–49 years), primary school or no formal education (versus middle school), having >1 child (versus 1 child), living in Northeast, Central, East, or North China (versus Southwest China), physical inactivity, hypertension, diabetes mellitus, and obesity were positively associated with the risk of total and ischemic stroke, whereas age 60 to 69 years and living with spouse or children (versus living alone) were negatively associated with the risk of total and ischemic stroke. Men, vegetable‐based diet, underweight, physical inactivity, hypertension, living in a high‐income region, having Urban Resident Basic Medical Insurance, and New Rural Cooperative Medical System were positively associated with the risk of hemorrhagic stroke, whereas age 60 to 69 years was negatively associated with the risk of hemorrhagic stroke.

Conclusions

We identified socioeconomic factors that complement traditional risk factors for incident stroke and its subtypes, allowing targeting these factors to reduce stroke burden.

Long-term Opioids Linked to Hypogonadism and the Role of Testosterone Supplementation Therapy

Opioids play a pivotal role in managing chronic pain with increasing prescription rates over the last few years. Hence, it is crucial to focus on the adverse effects of narcotics, and one of the lesser-known side effects is hypogonadism. Opioids act on the hypothalamus, pituitary, and directly on the gonads affecting serum testosterone levels. Narcotic-induced androgen insufficiency contributes to sexual dysfunction, infertility, hyperalgesia, and involving various body functions overall, affecting the quality of life. Opioid-induced hypogonadism is very challenging to diagnose for the clinicians, as the patients often under-report the symptoms. There are no established guidelines to analyze androgen insufficiency and dealing with their manifestations successfully. We did a substantial search in PubMed and Google Scholar, using various combinations of keywords to collect data to evaluate the impacts of opioids on serum testosterone levels. This study aims to highlight the clinical significance of opioid-induced androgen deficiency and the diagnostic techniques to recognize and credible treatment alternatives, including testosterone replacement therapy. Health care providers should screen the patients routinely for the signs and symptoms and monitor them often for the hormonal changes to select the patients cautiously for testosterone replacement therapy.

Testosterone therapy in hypogonadal patients and the associated risks of cardiovascular events

Since the male secondary sex characters, libido and fertility are attributed to their major androgen hormone testosterone, the sub-optimum levels of testosterone in young adults may cause infertility and irregularities in their sexual behaviour. Such deficiency is often secondary to maladies involving testes, pituitary or hypothalamus that could be treated with an administration of exogenous testosterone. In the last few decades, the number of testosterone prescriptions has markedly increased to treat sub-optimal serum levels even though its administration in such conditions is not yet approved. On account of its associated cardiovascular hazards, the food and drug authority in the United States has issued safety alerts on testosterone replacement therapy (TRT). Owing to a great degree of conflict among their findings, the published clinical trials seem struggling in presenting a decisive opinion on the matter. Hence, the clinicians remain uncertain about the possible cardiovascular adversities while prescribing TRT in hypogonadal men. The uncertainty escalates even further while prescribing such therapy in older men with a previous history of cardiovascular ailments. In the current review, we analysed the pre-clinical and clinical studies to evaluate the physiological impact of testosterone on cardiovascular and related parameters. We have enlisted studies on the association of cardiovascular health and endogenous testosterone levels with a comprehensive analysis of epidemiological studies, clinical trials, and meta-analyses on the cardiovascular risk of TRT. The review is aimed to assist clinicians in making smart decisions regarding TRT in their patients.

Effectiveness of testosterone therapy in hypogonadal patients and its controversial adverse impact on the cardiovascular system

Testosterone is the major male hormone produced by testicles which are directly associated with man's appearance and secondary sexual developments. Androgen deficiency starts when the male hormonal level falls from its normal range though, in youngsters, the deficiency occurs due to disruption of the normal functioning of pituitary, hypothalamus glands, and testes. Thus, testosterone replacement therapy was already known for the treatment of androgen deficiency with lesser risks of producing cardiovascular problems. Since from previous years, the treatment threshold in the form of testosterone replacement therapy has effectively increased to that extent that it was prescribed for those conditions which it was considered as inappropriate. However, there are some research studies and clinical trials available that proposed the higher risk of inducing cardiovascular disease with the use of testosterone replacement therapy. Thus under the light of these results, the FDA has published the report of the increased risk of cardiovascular disease with the increased use of testosterone replacement therapy. Nevertheless, there is not a single trial available or designed that could evaluate the risk of cardiovascular events with the use of testosterone replacement therapy. As a result, the use of testosterone still questioned the cardiovascular safety of this replacement therapy. Thus, this literature outlines the distribution pattern of disease by investigating the data and link between serum testosterone level and the cardiovascular disease, also the prescription data of testosterone replacement therapy patients and their tendency of inducing cardiovascular disease, meta-analysis and the trials regarding testosterone replacement therapy and its connection with the risks of causing cardiovascular disease and lastly, the possible effects of testosterone replacement therapy on the cardiovascular system. This study aims to evaluate the available evidence regarding the use of testosterone replacement therapy when choosing it as a treatment plan for their patients.

Gonadal hormones and stroke risk: PCOS as a case study

It is well known that stroke incidence and outcome is sex-dependent and influenced by age and gonadal hormones. In post-menopausal and/or aged females, declining estrogen levels increases stroke risk. However, women who experience early menopause also have an increase in stroke risk. This suggests that, regardless of age, gonadal hormones regulate stroke risk and severity. This review discusses prolonged gonadal hormone dysfunction in a common female endocrine disorder known as polycystic ovarian syndrome, PCOS, and the associated increased risk of stroke due to resulting hyperandrogenism and metabolic comorbidities.

Androgens' effects on cerebrovascular function in health and disease

Androgens affect the cerebral vasculature and may contribute to sex differences in cerebrovascular diseases. Men are at a greater risk for stroke and vascular contributions to cognitive impairment and dementia (VCID) compared to women throughout much of the lifespan. The cerebral vasculature is a target for direct androgen actions, as it expresses several sex steroid receptors and metabolizing enzymes. Androgens’ actions on the cerebral vasculature are complex, as they have been shown to have both protective and detrimental effects, depending on factors such as age, dose, and disease state. When administered chronically, androgens are shown to be pro-angiogenic, promote vasoconstriction, and influence blood-brain barrier permeability. In addition to these direct effects of androgens on the cerebral vasculature, androgens also influence other vascular risk factors that may contribute to sex differences in cerebrovascular diseases. In men, low androgen levels have been linked to metabolic and cardiovascular diseases including hypertension, diabetes, hyperlipidemia, and obesity, which greatly increase the risk of stroke and VCID. Thus, a better understanding of androgens’ interactions with the cerebral vasculature under physiological and pathological conditions is of key importance.

Androgens In Men Study (AIMS): protocol for meta-analyses of individual participant data investigating associations of androgens with health outcomes in men

INTRODUCTION

This study aims to clarify the role(s) of endogenous sex hormones to influence health outcomes in men, specifically to define the associations of plasma testosterone with incidence of cardiovascular events, cancer, dementia and mortality risk, and to identify factors predicting testosterone concentrations. Data will be accrued from at least three Australian, two European and four North American population-based cohorts involving approximately 20 000 men.

METHODS AND ANALYSIS

Eligible studies include prospective cohort studies with baseline testosterone concentrations measured using mass spectrometry and 5 years of follow-up data on incident cardiovascular events, mortality, cancer diagnoses or deaths, new-onset dementia or decline in cognitive function recorded. Data for men, who were not taking androgens or drugs suppressing testosterone production, metabolism or action; and had no prior orchidectomy, are eligible. Systematic literature searches were conducted from 14 June 2019 to 31 December 2019, with no date range set for searches. Aggregate level data will be sought where individual participant data (IPD) are not available. One-stage IPD random-effects meta-analyses will be performed, using linear mixed models, generalised linear mixed models and either stratified or frailty-augmented Cox regression models. Heterogeneity in estimates from different studies will be quantified and bias investigated using funnel plots. Effect size estimates will be presented in forest plots and non-negligible heterogeneity and bias investigated using subgroup or meta-regression analyses.

ETHICS AND DISSEMINATION

Ethics approvals obtained for each of the participating cohorts state that participants have consented to have their data collected and used for research purposes. The Androgens In Men Study has been assessed as exempt from ethics review by the Human Ethics office at the University of Western Australia (file reference number RA/4/20/5014). Each of the component studies had obtained ethics approvals; please refer to respective component studies for details. Research findings will be disseminated to the scientific and broader community via the publication of four research articles, with each involving a separate set of IPD meta-analyses (articles will investigate different, distinct outcomes), at scientific conferences and meetings of relevant professional societies. Collaborating cohort studies will disseminate findings to study participants and local communities.

PROSPERO REGISTRATION NUMBER

CRD42019139668.

Androgens Stimulate EPC-Mediated Neovascularization and Are Associated with Increased Coronary Collateralization

Endothelial progenitor cells (EPCs) play a key role in neovascularization and have been linked to improved cardiovascular outcomes. Although there is a well-established inverse relationship between androgen levels and cardiovascular mortality in men, the role of androgens in EPC function is not fully understood. In this study, we investigated the effects of androgens on 2 subpopulations of EPCs, early EPCs (EEPCs) and late outgrowth EPCs (OECs), and their relationships with coronary collateralization. Early EPCs and OECs were isolated from the peripheral blood of young healthy men and treated with dihydrotestosterone (DHT) with or without androgen receptor (AR) antagonist, hydroxyflutamide, in vitro. Dihydrotestosterone treatment enhanced AR-mediated proliferation, migration, and tubulogenesis of EEPCs and OECs in a dose-dependent manner. Furthermore, DHT augmented EPC sensitivity to extracellular stimulation by vascular endothelial growth factor (VEGF) via increased surface VEGF receptor expression and AKT activation. In vivo, xenotransplantation of DHT pretreated human EPCs augmented blood flow recovery and angiogenesis in BALB/c nude male mice, compared to mice receiving untreated EPCs, following hindlimb ischemia. In particular, DHT pretreated human OECs exhibited higher reparative potential than EEPCs in augmenting postischemic blood flow recovery in mice. Furthermore, whole blood was collected from the coronary sinus of men with single vessel coronary artery disease (CAD) who underwent elective percutaneous intervention (n = 23). Coronary collateralization was assessed using the collateral flow index. Serum testosterone and EPC levels were measured. In men with CAD, circulating testosterone was positively associated with the extent of coronary collateralization and the levels of OECs. In conclusion, androgens enhance EPC function and promote neovascularization after ischemia in mice and are associated with coronary collateralization in men.

Testosterone replacement therapy and cardiovascular risk

Testosterone is the main male sex hormone and is essential for the maintenance of male secondary sexual characteristics and fertility. Androgen deficiency in young men owing to organic disease of the hypothalamus, pituitary gland or testes has been treated with testosterone replacement for decades without reports of increased cardiovascular events. In the past decade, the number of testosterone prescriptions issued for middle-aged or older men with either age-related or obesity-related decline in serum testosterone levels has increased exponentially even though these conditions are not approved indications for testosterone therapy. Some retrospective studies and randomized trials have suggested that testosterone replacement therapy increases the risk of cardiovascular disease, which has led the FDA to release a warning statement about the potential cardiovascular risks of testosterone replacement therapy. However, no trials of testosterone replacement therapy published to date were designed or adequately powered to assess cardiovascular events; therefore, the cardiovascular safety of this therapy remains unclear. In this Review, we provide an overview of epidemiological data on the association between serum levels of endogenous testosterone and cardiovascular disease, prescription database studies on the risk of cardiovascular disease in men receiving testosterone therapy, randomized trials and meta-analyses evaluating testosterone replacement therapy and its association with cardiovascular events and mechanistic studies on the effects of testosterone on the cardiovascular system. Our aim is to help clinicians to make informed decisions when considering testosterone replacement therapy in their patients.

The role of bioidentical hormone replacement therapy in anti-aging medicine: a review of the literature

The changes in skin and overall appearance that occur with increasing age can be partly attributed to declining hormone levels. While hormonal deficiencies are most commonly associated with postmenopausal females, males are also subject to age-related testosterone decline and may benefit from replacement of deficient hormones. However, great disparities exist between the recommendations of scientific societies and actual use of hormone supplements in aging patients. The purpose of this literature review is to discuss the role of hormones in the aging process of the skin, explain the safety profile of hormone replacement therapy, specifically discussing the superiority of bioidentical hormones, and highlight the benefits of hormone replacement in anti-aging of the skin. In summary, this literature review suggests that hormone replacement with bioidentical hormones is a safe and effective way to prevent skin aging.